Insecticide Resistance Status of the Most Prevalent Mosquito Species in Awka, Anambra State

Abstract

Development of resistance in some local populations of mosquitoes has been reported as one of the major challenges faced in the control of mosquito borne diseases. This research therefore aimed to determine the insecticide resistant status of the most prevalent mosquito species in Awka Anambra State of Nigeria, using both cross-sectional and completely randomized designs. The research was conducted using 3 sentinel sites, 60 households and laboratory environment. Mosquitoes were collected, reared and identified using standard techniques. Insecticide susceptibility test was also carried out using standard procedures and test kits. Data collected were analyzed using Friedman test and ANOVA at 5 % significance level. A total of 1,022 larvae of mosquito were collected from the sentinel sites, out of that, 785 (76.81%) adults successfully emerged in the insectary. Using Pyrethrum Knockdown Collection (PKC) and Human Landing Catch (HLC), 207 and 183 adult mosquitoes were collected respectively. Three genera of mosquitoes: Anopheles, Aedes and Culex, were identified. The most abundant species (60.6 %; n = 709) collected was C. quinquefasciatus while the least abundant (3.42 %; n = 40) was Aedes vitattus (P = 0.000). Knockdown responses of the C. quinquefasciatus exposed to different classes of insecticides was progressively highest (83.0 % to 100 %) with Deltamethrin (0.03 %), from 10 to 60 minutes of exposure. The KDT50 (95 % CI) and KDT95 (95 % CI) for Deltamethrin (0.03 %), were 3.99 (0.00-7.52) and 14.64 (8.43-44.74) respectively. Mortality reponses of C. quinquefasciatus were 100 % (25.00±0.00) for Pirimiphos-methyl (0.25%), Bendiocarb (0.01%), and Deltamethrin (0.03%); and 81.0 % (20.25±0.96) for DDT.  This study showed that C. quinquefasciatus abounds and could be of major public health importance in disease transmission in the study area. Individuals belonging to local population of C. quinquefasciatus that can to survive the insecticide exposure have higher tendency of developing resistance to such insecticide. It therefore highlighted the need for ongoing monitoring and research into resistance development and the resistance status of local mosquito populations.